1. Field of the Invention
The present invention relates to a method of manufacturing microneedles, and more specifically, to a method of manufacturing hollow microneedles having inclined end tips.
2. Discussion of Related Art
In the field of bio-microelectromechanical systems (bio-MEMS) technology, samples may need to be pretreated in order to enable early detection and chemical analysis for diseases on small chips. This requires collecting blood while minimizing pain. Accordingly, an essential component called a microneedle is required.
In general, needles are variously utilized in hospitals. For example, the needles are used to collect biomaterials, such as blood, in order to detect diseases, inject drugs into the living body, or perform cosmetic treatment of the skin.
A vast amount of research has been conducted on developing various applicable bioanalysis chips all over the world.
However, conventional needles used to collect biomaterials, such as blood, are practically problematic because they may cause pain during use and inflict external injuries.
Therefore, the demand for new microneedles capable of collecting blood while minimizing pain has increased globally.
Conventionally, probe-type microspikes, solid microneedles, and hollow microneedles have been proposed.
Compared to conventional needles, microneedles are capable of minimizing pain during penetration into the skin without leaving external injuries.
In order to minimize pain while penetrating the skin, a top diameter of a needle is important in providing more opportunities to avoid pain spots on the skin. Above all, a microneedle should penetrate a stratum corneum and a epidermis having a thickness of about 10 to 20 μm and 100 μm, respectively. To do this, the microneedle needs to have a certain degree of physical strength.
In addition, a microneedle should have an appropriate length as to reach as far as a capillary vessel in order to effectively collect blood or transmit medicine.
In consideration of all the above-described points, a technique of manufacturing a solid silicon microneedle having an out-of-plane shape using silicon MEMS technology has been introduced. However, this technique requires an additional etching process to provide a hollow needle shape, or does not satisfy a required needle length.
Meanwhile, although a microneedle having a sufficient length has recently been proposed using a drawing method, the proposed microneedle neither ensures verticality and uniformity nor realizes process simplification.